The assembly government also revealed £48,000 spending on plants
Bonuses to top civil servants in Wales have risen 154% in the past five years, according to figures obtained by the Conservatives.
They show senior assembly government staff received more than £686,000 last year, compared to £270,000 in 2003/04.
The Tories said it showed a "money for nothing culture" in Cardiff Bay.
But the assembly government said it did not decide bonuses. The First Division Association union said only staff who achieve their objectives received them.
Conservatives called for a review of senior staff salaries after their written questions revealed details of the highest earners among administration senior staff.
The figures show overall assembly government staffing costs for 2006/7 were just over £224m, with staffing levels of 6,230 at 31 January this year.
A total of 772 people (12%) have salaries of more than £50,000 per year, while 28 officials are paid more than £100,000.
Opposition leader Nick Bourne said: "I find it incredible that the Labour-Plaid government has the brass neck to award staff such whopping bonuses when it has been failing on so many fronts over the last 12 months.
"Year after year Rhodri Morgan has spent more taxpayers' money on spin, presentation, advisers, and bureaucracy.
"This is money which should go on health, education and local government, not to fund an administration whose policies suffocate choice, enterprise and innovation."
A Welsh Assembly Government spokersperson said: "These very senior staff form part of the senior civil service and their pay and bonus policies are determined by the Treasury and Cabinet Office, not by the assembly government or other devolved administrations.
"To attract and retain high calibre staff we need to reflect market values.
"But recent senior staff review board findings show that senior civil service salaries have fallen behind those in other areas of the public sector, notably NHS and local government."
"Bonus payments are not permanent and are non-pensionable. In effect, base pay is being held down in favour of one-off payments that do not affect future levels of pay or pension."
Paul Neilson, First Division Association's national officer for Wales, said: "Far from being a 'money for nothing culture', those who do not achieve their objectives will not get any pay increases".
The figures emerged as the assembly government published the results of Freedom of Information (FoI) requests on spending on plants and promotional bags.
In 2003/04, the assembly government spent £795 on plastic bags. By 2007/08, it said it spent nothing on plastic bags, and £6,868 on bio-degradable and reusable drawstring bags.
However, the assembly government's FoI response referred only to plastic bags. It later issued a statement which said it had completely phased out plastic bags over the past five years, and now used only either bio-degradable or reusable drawstring bags.
The period covered the merger of quangos Welsh Development Agency, Wales Tourist Board and Elwa into the assembly government, and the figures for 2003 - 06 do not include spending on plastic bags for marketing purposes by those organisations.
The second FoI result revealed spending on office plants and landscaping rose from £25,896 in 2004/05 to £48,789 in 2007/08.
The spending was in the main Cathays Park building and five regional offices until 2005/06 when six further regional offices were added after the quango mergers.
In a statement accompanying the disclosure, the assembly government said: "Plants have been shown to not only enhance the perception of a building that leads to lower employee turnover rates... they also provide a cleaner, healthier environment by removing harmful pollutants from the air and stabilising humidity in the air."